If something is objective, then it is based on empirical, observable data without applying personal preconceptions or experience. It is the opposite of subjective.
Objectivity and Credibility
Credibility-enhancing actions include: Showing you care about the other person and have their best interests at heart. 
Language that reduces credibility includes: Totally and absolutely excessive exaggeration. Ibidem
Be objective and specific and support what you say with evidence, such as facts, statistics or testimonials. Be even-handed; If you are presenting possibilities, give all options a fair hearing and don’t leave out important information. If your reader finds out you’ve omitted key facts, you’ll lose credibility.
|“||The merits of each evaluation role will be discussed as to its relationship with credibility, objectivity, independence and usefulness.||”|